1-Phenyl-2-propanone (P2P) synthesis from Diethyl(phenylacetyl)malonate
- Thread starter G.Patton
- Start date
Do you mean simple distillation instead of vacuum one? You can, 216 deg C is boiling point at normal conditions.
Guys, do not fall for the cult of the holy reflux. Refluxing has no worth in itself except for the illusion of something happening which it creates.
With H2SO4 and Oxalic acid (best) but Phosphoric Acid and about any organic acid like Acetic or Formic or Citric work one gets next to quantitative yields if one heats up the mixture slowly over two hours to NOT MORE then 95 °C, holds it there for 30 minutes and then let it cool down. Add a small amount of solvent other then DCM (Toluene, Xylene, Ether) as organic acid may fall out and so collecting from top is advised. Petrol Ether 40/60 can be used and not much is needed but you get THREE layers in the end: Top layer is Pet-Ether with P2P dissolved. Middle layer is P2P with Pet-Ether dissolved*. And below is the acid mix (which can be re-used btw. without problems).
*Sounds funny but thats how it is: Both, Pet-Ether and P2P dissolve some of the other one but thex are not freely miscible. And so you get the three layers which drove me next to nuts already a long time ago. Until I figured this out.......
200 g Oxalic Acid Dihydrate
300 ml Water
100 ml H2SO4 37% (battery acid)
not all Oxalic Acid will dissolve - no problem
With this one can process a minimum 200 ml 20230 red oil
Really strong stirring all the time is needed.
The water/acid mix can be re-used.
Not over 95 °C gives light yellow P2P directly without steam or other distillation.
When you use a sep-funnel you best separate as long its still hot and the oxalic does not drop out.Or you put it in a beaker in the freezer with the bottom of the beaker touching the cold so it starts to crystallize from there. If you do this you need no solvent at all, the acid and watere crystallizing from the bottom will drive the P2P to the top and you can just pour it out after two or three hours and NO P2P will be left back.
I did a lot of work on this one, lol
With H2SO4 and Oxalic acid (best) but Phosphoric Acid and about any organic acid like Acetic or Formic or Citric work one gets next to quantitative yields if one heats up the mixture slowly over two hours to NOT MORE then 95 °C, holds it there for 30 minutes and then let it cool down. Add a small amount of solvent other then DCM (Toluene, Xylene, Ether) as organic acid may fall out and so collecting from top is advised. Petrol Ether 40/60 can be used and not much is needed but you get THREE layers in the end: Top layer is Pet-Ether with P2P dissolved. Middle layer is P2P with Pet-Ether dissolved*. And below is the acid mix (which can be re-used btw. without problems).
*Sounds funny but thats how it is: Both, Pet-Ether and P2P dissolve some of the other one but thex are not freely miscible. And so you get the three layers which drove me next to nuts already a long time ago. Until I figured this out.......
200 g Oxalic Acid Dihydrate
300 ml Water
100 ml H2SO4 37% (battery acid)
not all Oxalic Acid will dissolve - no problem
With this one can process a minimum 200 ml 20230 red oil
Really strong stirring all the time is needed.
The water/acid mix can be re-used.
Not over 95 °C gives light yellow P2P directly without steam or other distillation.
When you use a sep-funnel you best separate as long its still hot and the oxalic does not drop out.Or you put it in a beaker in the freezer with the bottom of the beaker touching the cold so it starts to crystallize from there. If you do this you need no solvent at all, the acid and watere crystallizing from the bottom will drive the P2P to the top and you can just pour it out after two or three hours and NO P2P will be left back.
I did a lot of work on this one, lol
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- By w2x3f5
indicate the yield of the substance p2p please.
do you have red oil? strangely, I had yellow oil under the same number.
do you have red oil? strangely, I had yellow oil under the same number.
Is there any other way to isolate the phenylacetic acid besides putting it in the refrigerator? Will not separating affect my future work?
- By William D.
You can crystallize this in a cool place and filter after. In another case, you can distill the fractions. For the following steps, you cannot leave PPA.
I would like to know if this synthesis is also working with phosphoric acid ( h3pO4) I appreciate your work and time
And what would be the amount ( phosphoric acid 85%)
Currently performing a test on the substrate with 75% phosphoric acid. No exact amounts used.
Trying with about 1:2 (Precursor to Phosphoric acid), again no exact amounts used but will report back if it works at all.
Trying with about 1:2 (Precursor to Phosphoric acid), again no exact amounts used but will report back if it works at all.
Tests using 75% phosphoric acid 1:2 (substrate to acid). 1 hour and 30 minutes into the reaction. Took a small "sniff test" and I seem to be able to detect the distinct odour of phenyl-2-propanone.
Lots of bubbling in the reaction that started as early as 60 degress celcius.
Again no exact amounts was actually used as the substrate I tried was a sample purchase from a chinese vendor (not on this site). Red liquid just like the photos of the malonate everywhere, the smell was not super pleasant but not horrible. Around 100 euro per kilo (actually less considering shipping was included)
Lots of bubbling in the reaction that started as early as 60 degress celcius.
Again no exact amounts was actually used as the substrate I tried was a sample purchase from a chinese vendor (not on this site). Red liquid just like the photos of the malonate everywhere, the smell was not super pleasant but not horrible. Around 100 euro per kilo (actually less considering shipping was included)
2 hours and 23 minutes into the reaction and I can confirm 100% that 75% phosphoric acid definitely works. However the reaction is still bubbling from CO2 evolution, so the reaction is not done.
The smell of phenyl-2-propanone is now too strong to dispute. The substrate was legit.
Further experimentation needs to be done to determine optimal amount of phosphoric acid.
Previous experience: [P2NP (from benzaldehyde & nitroethane) to phenyl-2-propanone with iron powder and HCL] and [MAPA to phenyl-2-propanone with hydrochloric acid])
If I remember correctly the p2np to phenyl-2-propanone with iron powder and HCL sometimes produced phenyl-2-propanone with an acrid smell. however the smell of the phenyl-2-propanone from the malonate is extremely sweet and that of pure phenyl-2-propanone.
Will store the resulting phenyl-2-propanone as a powder by reacting it with metabisulfite.
edit: Also beware of alibaba sellers of BMK precursors, one of them was not legit. (check the bot reviews, the fake sellers strictly sell precursors and have fake reviews of GBL and synthetic cannabinoid indole derivatives)
The smell of phenyl-2-propanone is now too strong to dispute. The substrate was legit.
Further experimentation needs to be done to determine optimal amount of phosphoric acid.
Previous experience: [P2NP (from benzaldehyde & nitroethane) to phenyl-2-propanone with iron powder and HCL] and [MAPA to phenyl-2-propanone with hydrochloric acid])
If I remember correctly the p2np to phenyl-2-propanone with iron powder and HCL sometimes produced phenyl-2-propanone with an acrid smell. however the smell of the phenyl-2-propanone from the malonate is extremely sweet and that of pure phenyl-2-propanone.
Will store the resulting phenyl-2-propanone as a powder by reacting it with metabisulfite.
edit: Also beware of alibaba sellers of BMK precursors, one of them was not legit. (check the bot reviews, the fake sellers strictly sell precursors and have fake reviews of GBL and synthetic cannabinoid indole derivatives)
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Appreciate your work hope we can get a detailed syntheses of phosphoric acid. I have 85% of phosphoric acid and hope to find a way that is working
Take notice: Ignore the 5 hour bullshit, it was not enough for me with 75% phosphoric acid. I ended up with way too much oil than theoretically possible. i.e. it was a mixture of the precursor and product, the precursor had not fully reacted. (I also detected the precursor smell when working up the reaction). This is a big problem according to me as they are annoying to separate from eachother. Therefor it is important, imo, to run the reaction to completion, I'd rather have bi-products or some slight polymerisation from running the reaction longer than unreacted precursor.
Better to end the reaction when it no longer is bubbling or bubbling very little.
Also don't wait for a detailed guide. Just try it yourself using small amounts.
Either use a 1:1 or 1:2 ratio of precursor to phosphoric acid. This is not that complex.
Better to end the reaction when it no longer is bubbling or bubbling very little.
Also don't wait for a detailed guide. Just try it yourself using small amounts.
Either use a 1:1 or 1:2 ratio of precursor to phosphoric acid. This is not that complex.
May I ask which solvent can be used instead of ether?
Use any compatible solvent, Such as DCM, MTBE etc etc.
The solvent needs to follow 2 criteria,
* Should not be too easy to hydrolyse (e.g. ethyl acetate hydrolyses in basic conditions, so if used you have to minimize it by either low % NaOH solution or be fast)
* Needs to be non polar and not misicible/soluble in water.
Preferably low boiling point so it can be removed easy later, but if that is not a concern for you
you also got things like toluene
I currently use an ether but not diethyl.
The solvent needs to follow 2 criteria,
* Should not be too easy to hydrolyse (e.g. ethyl acetate hydrolyses in basic conditions, so if used you have to minimize it by either low % NaOH solution or be fast)
* Needs to be non polar and not misicible/soluble in water.
Preferably low boiling point so it can be removed easy later, but if that is not a concern for you
you also got things like toluene
I currently use an ether but not diethyl.
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May I ask if I can still succeed by adding 20% alkaline solution after heating and refluxing, but the pH value can only reach 7?
Sorry you have to be clearer in your writing mate.
An alkaline solution can never be below 7, alkaline is just chemistry speech for "basic" (i.e. above 7 on the pH scale)
Why is it important for you too not go below 7? (or above 7)?
Please tell me which reaction and chemicals you intend or are currently using. You doing the sulfuric acid variant, phosphoric acid or saponification + hydrochloric acid variant?
An alkaline solution can never be below 7, alkaline is just chemistry speech for "basic" (i.e. above 7 on the pH scale)
Why is it important for you too not go below 7? (or above 7)?
Please tell me which reaction and chemicals you intend or are currently using. You doing the sulfuric acid variant, phosphoric acid or saponification + hydrochloric acid variant?
Heating reflux for 5 hours, adding 20% sodium hydroxide solution to the ice bath, the pH value is stuck at 7
Assume you meant you added the alkaline to the reaction mixture while it's in a ice bath. Anyway if the pH value is stuck at 7, your pH meter or pH paper doesn't work correctly. What are you using to measure the pH?
And what acid did you use?
Edit:
The first guy who replied to this thread said the following (note the pH thing with the saponification or whatever)
"Perform CAS 20320-59-6 official procedure After 4 hours of reaction at 80°C, stop heating, then adjust the alkali pH with sodium hydroxide, until 7, it can't go up, stratification appears, the oil layer is on top, and then ether extraction is added, and the stratification begins, and the ether layer is extracted, and the upper layer starts, and the distillation at atmospheric pressure at 220° keeps going up, and the temperature keeps it at 110°, and a lot of liquid is distilled, and I think it's ether, and then it starts to appear, and this phenomenon in the flask I thought it would be 216° distillation to produce P2P, but there is no problem How can I remedy it "
And what acid did you use?
Edit:
The first guy who replied to this thread said the following (note the pH thing with the saponification or whatever)
"Perform CAS 20320-59-6 official procedure After 4 hours of reaction at 80°C, stop heating, then adjust the alkali pH with sodium hydroxide, until 7, it can't go up, stratification appears, the oil layer is on top, and then ether extraction is added, and the stratification begins, and the ether layer is extracted, and the upper layer starts, and the distillation at atmospheric pressure at 220° keeps going up, and the temperature keeps it at 110°, and a lot of liquid is distilled, and I think it's ether, and then it starts to appear, and this phenomenon in the flask I thought it would be 216° distillation to produce P2P, but there is no problem How can I remedy it "
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